用.net 处理xmlHttp发送异步请求

我们要达到的目的是点击按钮，获得服务器的当前时间，aspx的html如下： Html <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Linkedu.Web.WebWWW.Default" %>

                         

        用Post方式获得服务器的当前时间                 用Get方式获得服务器的当前时间                

要用javascript 发送xmlHttp 请求必须解决的问题是跨浏览器的支持。我们把xmlHttp的发送封装在一个javascript对象中，同时在这个对象中解决了跨浏览器支持的问题。代码如下：

xmlHttp对象 /**//* url-loading object and a request queue built on top of it */

/**//* namespacing object */ var net=new Object();

net.READY_STATE_UNINITIALIZED=0; net.READY_STATE_LOADING=1; net.READY_STATE_LOADED=2; net.READY_STATE_INTERACTIVE=3; net.READY_STATE_COMPLETE=4;

/**//*--- content loader object for cross-browser requests ---*/ net.xmlHttp=function(url, onload, params, method, contentType, onerror){   this.req=null;   this.οnlοad=onload;   this.οnerrοr=(onerror) ? onerror : this.defaultError;   if(typeof(method) == "undefined" || method == null)   {     method = "POST";   }   this.loadXMLDoc(url, params, method, contentType); }

net.xmlHttp.prototype.loadXMLDoc=function(url, params, method, contentType){   if (!method){     method="GET";   }   if (!contentType && method=="POST"){     contentType='application/x-www-form-urlencoded';   }   if (window.XmlHttpRequest){     this.req=new XmlHttpRequest();   } else if (window.ActiveXObject){     this.req=new ActiveXObject("Microsoft.xmlHttp");   }   if (this.req){     try{       var loader=this;       this.req.onreadystatechange=function(){         net.xmlHttp.onReadyState.call(loader);       }       this.req.open(method,url,true);       if (contentType){         this.req.setRequestHeader('Content-Type', contentType);       }       this.req.send(params);     }catch (err){       this.onerror.call(this);     }   } }

net.xmlHttp.onReadyState=function(){   var req=this.req;   var ready=req.readyState;   if (ready==net.READY_STATE_COMPLETE){     var httpStatus=req.status;     if (httpStatus==200 || httpStatus==0){       this.onload.call(this);     }else{       this.onerror.call(this);     }   } }

net.xmlHttp.prototype.defaultError=function(){   alert("error fetching data!"     +"/n/nreadyState:"+this.req.readyState     +"/nstatus: "+this.req.status     +"/nheaders: "+this.req.getAllResponseHeaders()); }

 

下面开始写发送xmlHttp请求的代码：

default.js //全局xmlHttp对象 var cobj;

/**//* Post begin*/ //绑定Post发送xmlHttp事件到btnTestPost function loadTestPost() {    var iobj = document.getElementById("btnTestPost");    //btnTestPost按钮监听的绑定    var clickRouter=new jsEvent.EventRouter(iobj,"onclick");    clickRouter.addListener(btnTestPostClick); } function btnTestPostClick() {   // open参数 url, onload, params, method, contentType, onerror     cobj = new net.xmlHttp("DefaultHandler.ashx",dealResult, "", "POST"); } /**//* Post end*/

/**//* Get begin*/ //绑定Get发送xmlHttp事件到btnTestGet function loadTestGet() {    var iobj = document.getElementById("btnTestGet");    //btnTestGet按钮监听的绑定    var clickRouter=new jsEvent.EventRouter(iobj,"onclick");    clickRouter.addListener(btnTestGetClick); } function btnTestGetClick() {   //  open参数 url, onload, params, method, contentType, onerror     cobj = new net.xmlHttp("DefaultHandler.ashx?T=1",dealResult, null, "GET"); } /**//* Get end*/

 

function dealResult() {        var dobj = document.getElementById("divResult");     dobj.innerHTML =  cobj.req.responseXML.text; }

window.onload = function() {     //绑定Post发送xmlHttp事件到btnTestPost     loadTestPost();     //绑定Get发送xmlHttp事件到btnTestGet     loadTestGet(); };

最后是.net处理xmlHttp的代码 .net 处理xmlHttp请求 public class DefaultHandler : IHttpHandler     {         protected XmlDocument _xmlResult;

        public void ProcessRequest(HttpContext context)         {             if (context.Request["T"] != null)             {//GET xmlhttp测试                 context.Response.ContentType = "text/xml";                 XmlDocument xmlDoc = new XmlDocument();                 xmlDoc.LoadXml(string.Format(@"GET:{0}", System.DateTime.Now));                 xmlDoc.Save(context.Response.OutputStream);                 context.Response.End();             }             else             {//POST xmlhttp测试                 context.Response.ContentType = "text/xml";                 XmlDocument xmlDoc = new XmlDocument();                 xmlDoc.Load(context.Request.InputStream);                 if (xmlDoc.DocumentElement.Name == "T")                 {                     xmlDoc.LoadXml(string.Format(@"POST:{0}", System.DateTime.Now));                     xmlDoc.Save(context.Response.OutputStream);                     context.Response.End();                 }             }         }

        public bool IsReusable         {             get             {                 return false;             }         }     }